browser.omnibox.onDeleteSuggestion.addListener(listener)
browser.omnibox.onDeleteSuggestion.removeListener(listener)
browser.omnibox.onDeleteSuggestion.hasListener(listener)

Events have three functions:

addListener(listener)

Adds a listener to this event.

removeListener(listener)

Stop listening to this event. The listener argument is the listener to remove.

hasListener(listener)

Check whether listener is registered for this event. Returns true if it is listening, false otherwise.

text

string. The description of the deleted suggestion.

This example prints the deleted suggestion to the console:

function logDeletedSuggestion(text) {
  console.log(`The user deleted: ${text}`);
}

browser.omnibox.onDeleteSuggestion.addListener(logDeletedSuggestion);